/*
*    Qizx/open 3.0 beta
*
* This code is the open-source version of Qizx.
* Copyright (C) 2004-2009 Axyana Software -- All rights reserved.
*
* The contents of this file are subject to the Mozilla Public License 
*  Version 1.1 (the "License"); you may not use this file except in 
*  compliance with the License. You may obtain a copy of the License at
*  http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
*  WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
*  for the specific language governing rights and limitations under the
*  License.
*
* The Initial Developer of the Original Code is Xavier Franc - Axyana Software.
*
*/
using System;
namespace System.Qizx.Queries.Iterators
{
	
	
	/// <summary> A Phrase is simply an ordered All with a window constraint.
	/// 
	/// </summary>
	public class PhraseIterator:AllIterator
	{
		/// <summary> </summary>
		/// <param name="variable">true if items of phrase are not simple words, but Or's
		/// of words or phrases due to Thesaurus expansion. In that case the test
		/// based on window does not work.
		/// </param>
		public PhraseIterator(PostingIterator[] iterators, bool variable):base(iterators)
		{
			setOrdered(true);
			if (variable)
				setDistanceConstraint(0, 0);
			// less expensive than distance = 0: 
			else
				WindowConstraint = iterators.Length;
		}
		
		public override PostingIterator bornAgain()
		{
			return copyConstraints(new PhraseIterator(copy(iterators), constraints.window < 0));
		}
	}
}